PURPOSE: To enable the mechanical access of a cylindrical abrasive easily and properly to the polishing surface of even a complicate shape workpiece and ensure highly efficient polishing by holding the abrasive connected to a driving rotary axis via a plate spring.

CONSTITUTION: A driving rotary axis 2 is so connected with a cylindrical abrasive 16 as to be enclosed therewith in the same direction via a radially-shaped plate spring 12. Through the deformation of the plate spring 12, the abrasive 16 shifts relatively for the axis 2 within an allowance of coupling between small through-holes on ring-shaped plates 18 and 18a and a pin 24 on a disc member, and mechanically has automatic access to the polishing surface of a complicate shape workpiece easily and properly, thereby polishing the workpiece uniformly enough at high efficiency.